Method of making fasteners



Fttl'). 26, 1935. SUNDBACK 1,992,254

METHOD OF MAKING FASTENERS Original Filed Dec. 14, 1929 I INVENIdR; Q'aeon fia'ndboc/f' Patented Feb. 26, 1935 i I v UNITED STATES PATENT OFFICE 1 METHOD 'OF MAKING FASTENERS Gideon Sundback, Meadville, Pa., assignor to Hookless Fastener Company, Meadville, Pa., a corporation of Pennsylvania Application December 14, 1929, Serial No. 414,157 Renewed December 14, 1932 6 Claims. (Cl. 29-148) My invention relates to slide fasteners of the stringers which in the drawing are designated 10 type having a pair of flexible stringers, usually each having a series of spaced fastener elements fabric tape, held together by two series of inter- 11, attached along one edge,' the fastener elelocking elements secured to the adjacent edges of ments on opposite stringers being arranged in the tapes, and interlocked or released by a slider, staggered relation. A slider 12 is usually em- 5 and is concerned especially with a method of played to bring the fastener elements together making the interlocking elements. successively at an angle to each other and to Heretofore it has been usual to form interlockinterlock the fastener elements progressively as ing elements by stamping or forging from blank it travels along the stringers. The slider illusor strip stock with suitable punches and dies. trated comprises apair of overlying spaced wings 10 These methods produce a satisfactory fastener, 12a positioned on opposite sides of the stringers but usually either involve a relatively large the upper wing before removed in Fig. 1 and has amount of scrap, or else require expensive prea Y-shaped channel through which the fastener formed stock. 1 elements pass during travel of the slider.- The It is one of my objects to provide a less expenspaced wings are connected by an integral wedge 15 sive process of manufacture involving no scrap, shaped portion 13 and a pull member .14 is suitand using a readily available and cheap form of ably connected to the slider in a manner not stock, namely round wire. illustrated. In order to provide a more secure Another object of the invention is to bend the connection of the fastener elements to the stringround wire blanksand apply them to the tapes 'ers, each of the stringers is provided with a corded 0 and thereafter deform or forge them to provide edge 15 which is preferably made as seen in Fig. the interlocking portions proper of the interlock- 7 by attaching cords 16 and 17 to opposite sides ing elements. of one edge of a flat-flexible strip or tape 18.

In the accompanying drawing, '1 have shown The fastener elements 11 are alike on both for purposes of illustration two embodiments stringers and adescription of the construction of 25 which my invention may assume in practice. In one of the elements will .be sufficient. Such anthe drawing: 0 element preferably comprises a wire bent to sub- Fig. 1 is a plan view of a fastener constructed stantially a U-shape was to provide spaced side. according to my invention with a part of the portions 19 and 20 to grip the corded edge 15.

slider shown in section to illustrate the inter- The side portions arejoined by anintegral conlocking principle. necting portion 21 at the bend in the wire which Fig. 2 is a longitudinal sectional view on the on one side is formed into an interlocking proline 2--2.of Fig. 1 showing the fastener elements jection 22. This projection interlocks with a interlocked. recess or slot 23 on the next adjacent fastener Fig. 3 illustratesa step in one embodiment of element which recess in the present construcmy improved method for making fasteners, .the tion, is provided by the space between the side forming tool being shown both in' side and plan portions of the wire and in front of the corded elevation. edge of the tape. Thus no special formation of Fig. 4 is a front elevation of a fastener element an interlocking recess is required. The side por- 40 made according to the method shown in Fig. 3. tions 19 and 20 are flattened out to provide suit- 40 Fig. 5 ma side elevation of a-wire blank from able recesses 24 and 25' to receive the-corded edge which a fastener element is made. of the stringer.

Fig. 6 is a plan of the same blank. The steps in my improved method for making stringer showing the blank bent and applied to 5 and 6 is illustrated a wire blank 26 which the tape before being formed as shown in Fig. 3. is preferably cut from a straight round wire.

' Fig. 8 is a front elevation view of a portion of The indentations or recesses 24 and- 25 may be a fastener stringer illustrating a second embodiformed in the wire before the blank is cut by ment of my improved method for making fastensuitable roller dies or may, if desired, be formed ers. after the wire is cutinto blanks. The blanks 50 Fig. 9 is a plan View of a portion of a fastener are preferably tumbled so as to remove all'burrs stringer having elements constructed according and sharp edges and are next placed .through to the method shown in Fig. 8. 1 any suitablehopper, not shown, which arranges Fastening devices of the type to which my inthem in proper relation for clamping to the vention relates usually comprise a pair of flexible corded edge of the tape. Fig. 7 illustrates the 55 Fig. '7 Ba cross-sectional view. through a fasteners will now be briefly described, In Figs.

stringer.

mechanism at an acute angle to the plane of the fastener element and the nose portion 29 of the tool enters between two adjacent fastener elements. The V-shaped recess squeezes up the metal from opposite sides of, the connecting portion 21 of the wire blank, thus providing two burrs which merge together to form the single projection 22. The bottom of the V-shaped recess indicated by the line 30, is inclined relative to the plane of the tool so as properly to form the front portion of the projection 22. A front elevation of an element so constructed is illustrated in Fig. 4.

A modification of this method and one which may be preferred in some instances is illustrated in Figs. 8 and 9. A pair of side tools 31 and 32 are reciprocated by suitable mechanism in a direction perpendicular to the plane of the stringers and their front ends enter between adjacent fastener elements. One corner of each of the elements is rounded as indicated at 33 and these corners act to squeeze up metal from the under side of the fastener element into two burrs which merge together and form the projection 22.

operation by the side tools entering between the fastener elements. The fastener stringer is progressively fed along during reciprocation of the tools and the interlocking projections are formed one at a time on all of the elements along the stringer.

As a result of my invention it will be observed that an improved method has been devised for making fastener elements which is particularly adapted to fastener elements of the bent Wire type. The material is deformed from the sides of the Wire instead of from the inner part of the bend and thus, the fastener element is not weakened in any way and in fact, is strengthened to some extent. This is due to the fact that the transverse cross-section at the bend is increased rather than decreased, and since the cross-section at this point determines the resistance to spreading apart of the sides of .the elements which embrace the tape, the advantages of my improved construction and method will be readily apparent.

The novel and advantageous features of fastener construction herein disclosed will be claimed in a divisional application.

In either Figs. 3 or 8 the fastener element- 'may be suitably supported during the squeezing While I have in this application specifically described two embodiments which my invention may assume in practice, it will be understood that these embodiments are merely for the purposes of illustration and description and that various other forms may be devised within the scope of my invention as defined in the appendedclaims.

What I claim as my invention is:

1. The method of making a fastener element comprising forming attaching means in portions of a blank, bending said blank about its central portion until said attaching portions are opposed,

U-shape and then deforming material adjacent said bend in substantially the direction in which said wire extends at thebend toform an inter-; locking projection.

3. The method of making a fastener element comprising forming clamping means adjacent the ends of a round wire blank, bending the blank to substantially U-shape around the edge of a stringer, and then deforming material from the sides of said .blank at the bend in a direction perpendicular to the plane of the stringer to provide aninterlocking projection.

4. The method of forming a fastener element comprising bending a wire blank around the edge of a flexible stringer, and then scraping up material from opposite edges on one side of said ele-- ment in a transverse direction toward the longitudinal center line of the element to form an interlocking projection.

5. The method of making a fastener stringer comprising securing blanks in spaced relation to the edge of a stringer element, and then deforming material at the free end of each of said ele ments by means entering betweena pair of elements to scrape up material from opposite edges on one side of the element toward the transverse center line thereof to form an interlocking projection on each element.

6. The method of making a fastener stringer comprising bending a series of wire blanks to of the element toward the longitudinal center line thereof to form an interlocking projection on each of the elements.

GIDEON SUNDBACK. 

